New techniques for studying normal masticatory behavior have been developed. Interrelationships of food consistency, occlusal movements between teeth, activity sequences and forces of the masticatory and hyoid muscles, movements of the jaw and hyoid, the central nervous system, and peripheral sensory feedback are being explored in an integrated fashion through coupled cinefluoroscopy and electromyography and through neurophysiological approaches. A range of mammals including the echidna, opposum, tenrec, hyrax and various primates are being investigated to determine the above interrelationships. The feeding patterns of these mammals seem to be simple modifications of a basic patterns; rhythmic jaw activity being determined by a central generator capable of modification from peripheral sensory input. The purpose of this study is twofold: 1) to substantiate the universality of normal masticatory behavior through a wide taxonomic range of mammals, 2) to explore the neurophysical control mechanisms governing masticatory behavior. The techniques of these investigations are not directly applicable to man, but our demonstration that the basic pattern of jaw and hyoid movement is independent of morphological differences in oral structures suggests that the results of this work will be applicable to man, providing an analogue for the experimental investigation of his functional disturbances. BIBLIOGRAPHIC REFERENCES: Crompton, A.W., Thexton, A.J., Hiiemae, Karen and Cook, Pamela, 1976. (anticipated - Sept/Oct). The activity of the hyoid and jaw muscles during the chewing of soft food in the American opossum. In Biology and Environment, Vol. 2: "Biology of Marsupials" Ed. D. Gilmore and B. Stonehoue. Macmillan, London. Crompton, A.W. and Kielan-Jaworowska, Zofia, 1977 (anticipated). "Molar structure and occlusion in Cretaceous Mammals" in Development Function and Evolution of Teeth. Ed. P.M. Butler and K.A. Joysey. Academic Press, London.